How PCs Work

Since the first PC hit the market, newer and better models have made older models obsolete within months of production. Drive technologies like SATA replaced IDE, and PCI expansion slots replaced ISA and EISA. The most prominent gauge for technological progress in a PC, though, is its CPU and the microprocessor within that CPU.

Silicon microprocessors have been the heart of the computing world since the 1950s. During that time, microprocessor manufacturers have crammed more transistors and enhancements onto microprocessors. In 1965, Intel founder Gordon Moore predicted that microprocessors would double in complexity every two years. Since then, that complexity has doubled every 18 months, and industry experts dubbed the prediction Moore's Law. Many experts have predicted that Moore's Law will reach an end soon because of the physical limitations of silicon microprocessors [source: PBS].

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As of this writing, though, processors' transistor capacities continue to rise. This is because chip manufacturers are constantly finding new ways to etch transistors onto the silicon. The tiny transistors are now measured in nanometers, which is one billionth of a meter. Atoms themselves are approximately 0.5 nm, and the most current production processes for microprocessors can produce transistors that measure 45 nm or 32 nm. The smaller that number goes, the more transistors will fit onto a chip and, thus, the more processing power the chip is capable of. As of May 2011, Intel was working on a 22-nm manufacturing process, code-named Ivy Bridge, which uses transistors with an energy-conserving design called Tri-Gate [sources: BBC, Intel].

So what happens when we reach the end of Moore's Law? A new means of processing data could ensure that progress continues. Potential successors are those that prove to be a more powerful means of performing the basic computational functions of a processor. Silicon microprocessors have relied on the traditional two-state transistor for more than 50 years, but inventions such as quantum computers are changing the game.

Quantum computers aren't limited to the two states of 1 or 0. They encode information as quantum bits, or qubits. A qubit can be a 1 or a 0, or it can exist in a superposition that is simultaneously 1 and 0 or somewhere in between. Qubits represent atoms that are working together to serve as both computer memory and microprocessor. Because a quantum computer can contain these multiple states simultaneously, it has the potential to be millions of times more powerful than today's most powerful supercomputers. Quantum computing technology is still in its early stages, but scientists are already proving the concept with real, measurable results. Be sure to check out How Quantum Computers Work for more on this amazing breakthrough.

Time will tell whether the power of quantum computers will ever make it to the average PC. In the meantime, you can still carry a lot of processing power with you thanks to mobile PCs, which we'll look at next.